a bare bones node module for building JSON API v1.0 compliant payloads.
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README.md

transformalizer

a bare bones node module for transforming raw data into JSON API v1.0 compliant payloads.

this module:

  • makes no assumption regarding the shape of your data or the datastores/sdks used.
  • supports the full JSON API v1.0 specification
  • supports dynamic transformations, links, and meta at all levels of a document

Installing

$ npm install --save transformalizer

Getting Started

Create a new transformalizer and register schemas

import createTransformalizer from 'transformalizer';

// create a new transformalizer
const transformalizer = createTransformalizer();

// register a schema
transformalizer.register({
  name: 'article',
  schema: { /* see below for schema details and examples */ },
});

// transform raw data into a valid JSON API v1.0 document
const document = transformalizer.transform({ name: 'article', source });
console.log(JSON.stringify(document));

Examples

See examples in the examples folder of this repository.

API

createTransformalizer([options]) => transformalizer

Create a new transformalizer object

Parameters
Name Type Description
[options={}] Object global options shared between all schemas
Examples
const createTransformalizer = require('transformalizer')

const transformalizer = createTransformalizer()

transformalizer.register(params)

Register a new document schema.

Parameters
Name Type Description
params Object
params.name String schema name
params.schema Object mappings for type, see Schema for more details
Examples
transformalizer.register({
  name: 'blog-post',
  schema: {
    // ..
  }
})

transformalizer.transform(params) => Object

Build a json api document using the schema with specified name and with the given source data.

Parameters
Name Type Description
params Object
params.name String the name of the schema to use
params.source Object Object[]
[params.options={}] Object additional data to be passed to transform functions, this will be merged with the global options
Examples
const blogPost = { title: 'Hello, World!', body: 'To be continued...', createdAt: new Date() }
const document = transformalizer.transform({ name: 'blog-post', source: blogPost })

transformalizer.untransform(params) => Object

Reconstruct data objects from a json api document.

Parameters
Name Type Description
params Object
params.document Object json api document
params.options={} Object additional data to be passed to untransform functions, this will be merged with the global options
Examples
const payload = { data: { id: '1', type: 'blog-post', attributes: { title: 'Hello, World!', body: 'To be continued...', createdAt: '2017-09-19T13:10:00' } } }
const data = transformalizer.untransform({ document: payload })

Options

Global options are passed in when creating a new transformalizer object. Options can also be passed in when transforming source objects to the json-api format or untransforming a json-api document back to data objects.

Options for Untransforming Json-Api Documents
Name Type Description
untransformIncluded Boolean A value indicating whether included resources are untransformed back to data objects
nestIncluded Boolean A value indicating whether the full object hierarchy is recreated using the included data objects. Caveat: This can lead to circular references.
removeCircularDependencies Boolean A value indicating whether circular dependencies in the full object hierarchy should be removed. Caveat: This may lead to an unexpected object hierarchy depending on how the data relationships are structured.

Schema

A schema object defines a set of functions used to transform your raw data into a valid JSON API document. It has the following basic structure (that closely resembles a json api document), which is described in more detail below

{
  links({ source, options, data, included }) {
    return { /* top level links */ };
  },
  meta({ source, options, data, included }) {
    return { /* top level meta */ };
  },
  data: {
    dataSchema({ source, options, data }) {
      return 'other-schema-name';
    },
    untransformDataSchema({ type, resource, document, options }) {
      return 'my-type';
    },
    type({ source, options, data, state }) {
      return 'my-type';
    },
    id({ source, options, data, type, state }) {
      return data.id.toString();
    },
    untransformId({ id, type, options }) {
      return parseInt(id, 10);
    },
    attributes({ source, options, data, type, id, state }) {
      return { /* resource attributes */ }
    },
    untransformAttributes({ id, type, attributes, resource, options }) {
      return { /* resource attributes */ }
    },
    relationships: {
      // ..
      [key]({ source, options, data, type, id, attributes, state }) {
        return {
          data: {
            name: 'related-schema',
            data: { /* relationship data to be passed to other schema */ },
            included: true,
          },
          links: { /* relationship links if available */ },
          meta: { /* relationship meta if available */ }
        }
      },
      // ..
    },
    links({ source, options, data, type, id, attributes, relationships, state }) {
      return { /* resource links if available */ }
    },
    meta({ source, options, data, type, id, attributes, relationships, state }) {
      return { /* resource meta if available */ }
    }
  }
}

links(params) => Object optional

A function that should return the top level links object.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function, merged with the global options object
params.data Object the json api document data after transform
params.included Object[] the json api document included data after transform

meta(params) => Object optional

A function that should return the top level meta object.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function, merged with the global options object
params.data Object the json api document data after transform
params.included Object[] the json api document included data after transform

data.type(params) => String optional

A function that should return the type of the resource being processed. If this is not provided, the name of the schema will be used as the resource type.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.id(params) => String optional

A function that should return the id of the data object being processed. If this is not provided, it is assumed that the "id" of the resource is simply the "id" property of the source object.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.type String the resource type determined in the data.type step
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.untransformId(params) => Object optional

A function that should return the id of the resource being processed. If this is not provided, it is assumed that the "id" of the data object is simply the "id" property of the resource.

Parameters
Name Type Description
params Object
params.id String the resource id
params.type String the resource type
params.options Object any options passed to the #untransform function

data.attributes(params) => Object optional

A function that should return the attributes portion of the resource being processed. If a null or undefined value is returned, no attributes will be included on the resource.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.type String the resource type determined in the data.type step
params.id String the id of the current resource, determined in the data.id step
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.untransformAttributes(params) => Object optional

A function that should return the attributes portion of the data object being processed. If this is not provided, it is assumed that the attributes of the data object are simply the "attributes" property of the resource.

Parameters
Name Type Description
params Object
params.id Object the id of the current data object, determined in the data.untransformId step
params.type String the resource type
params.attributes Object the json-api resource object attributes
params.resource Object the full json-api resource object
params.options Object any options passed to the #untransform function

data.relationships.key(params) => Object optional

A map of relationship keys to functions that should return a valid relationship object with one caveat outlined below. If a null or undefined value is returned, that relationship will be excluded from the relationships object.

Caveat: The data property of the relationship object should either be a single object or an array of objects in the form shown below

{
  name: 'schemaName', // the name of the related schema to use to transform the related item
  data: { /* the "data" param to be passed to the related schema's functions */ },
  included: true, // optional, required if the related item should be included
  meta: { /* a meta object to be included on the resource identifier object */ }
}
Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.type String the resource type determined in the data.type step
params.id String the id of the current resource, determined in the data.id step
params.attributes Object the attributes object of the current resource, determined in the data.attributes step
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.links(params) => Object optional

A function that should return the links object for the current resource. If a null or undefined value is returned, no links will be included on the resource.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.type String the resource type determined in the data.type step
params.id String the id of the current resource, determined in the data.id step
params.attributes Object the attributes object of the current resource, determined in the data.attributes step
params.relationships Object the relationships object of the current resource, determined in the data.relationships step
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.meta(params) => Object optional

A function that should return the meta object for the current resource. If a null or undefined value is returned, no attributes will be included on the resource.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array
params.type String the resource type determined in the data.type step
params.id String the id of the current resource, determined in the data.id step
params.attributes Object the attributes object of the current resource, determined in the data.attributes step
params.relationships Object the relationships object of the current resource, determined in the data.relationships step
params.links Object the links object of the current resource, determined in the data.links step
params.state Object the recommended namespace for passing information between data level methods, useful for storing calculated data that is needed in multiple places

data.dataSchema(params) => String optional

A function that should return the name of a schema to use to transform the current source object. Useful for building documents who's primary data is a collection of multiple types.

Parameters
Name Type Description
params Object
params.source Object[],Object the source data passed to the #transform function
params.options Object any options passed to the #transform function
params.data Object the current item being processed when source is an array, or the source itself if not an array

data.untransformDataSchema(params) => String optional

A function that should return the name of a schema to use to untransform the current resource.

Parameters
Name Type Description
params Object
params.type String the resource type
params.resource Object the full json-api resource object
params.document Object the full json-api document
params.options Object any options passed to the #untransform function

Test

Run the test suite

$ npm test

Run coverage

$ npm run coverage

Contributing

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request

License

Copyright (c) 2017 Gaia. Licensed under the MIT license.